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Experiments find strongest shapes with 3-D printing

March 18, 2013
University of Chicago
Physicists are using 3-D printing to test complex qualities of shapes made via the computer. They are studying "jamming" and the structural properties of shapes.

Graduate student Marc Miskin manufactured granular materials of various shapes in a 3D printer to test their aggregate properties when jammed into a confined space.
Credit: Photo by Rob Kozloff

Prof. Heinrich Jaeger's research group examines materials and phenomena that appear simple at the surface, but which reveal tremendous complexity upon close examination. One such phenomenon is jamming, in which aggregates of randomly placed particles, including spheres or more complicated shapes, or even molecules, transition from fluid-like to solid-like behavior.

Jamming lends itself to soft robotics, in addition to other applications as explored in a workshop at the University of Chicago last October. In recent computer simulations and experiments, Jaeger, the William J. Friedman & Alicia Townsend Professor in Physics, and graduate student Marc Miskin investigate another aspect of jamming. They analyzed how the properties of a jammed material can be tuned by changing the shape of the constituent particles. Their results on "Adapting granular materials through artificial evolution" appeared Jan. 20 as an Advance Online Publication in Nature Materials.

Miskin and Jaeger addressed a daunting question in their research: Given a design goal for the jammed aggregate, for example to have it as stiff or as soft as possible in response to an applied force, what particle shape will best produce the desired outcome? For this complex optimization problem, they faced an infinite variety of shapes to choose from. So Miskin employed a computer algorithm -- referred to as an "evolutionary optimization" to answer this question.

The computer designed particles by starting from a random shape, and then iteratively altered its configuration, at each stage performing a series of simulations that tested how close the performance approximated the stated goal. Once an optimal shape was identified, Miskin then manufactured a large number of copies with the lab's 3D printer for testing in a vise-like squeezing apparatus to verify his algorithm's predictions.

Story Source:

Materials provided by University of Chicago. Original written by Steve Koppes. Note: Content may be edited for style and length.

Journal Reference:

  1. Marc Z. Miskin, Heinrich M. Jaeger. Adapting granular materials through artificial evolution. Nature Materials, 2013; DOI: 10.1038/nmat3543

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University of Chicago. "Experiments find strongest shapes with 3-D printing." ScienceDaily. ScienceDaily, 18 March 2013. <>.
University of Chicago. (2013, March 18). Experiments find strongest shapes with 3-D printing. ScienceDaily. Retrieved April 27, 2017 from
University of Chicago. "Experiments find strongest shapes with 3-D printing." ScienceDaily. (accessed April 27, 2017).